Internal combustion engine with shifting cylinders



April 9, 1963 M. E. LINDSAY 3,084,678

INTERNAL COMBUSTION ENGINE WITH SHIFTING CYLINDERS 4 Sheets-Sheet 1 Filed April 15, 1960 INVENTOR.

lfAl/R/CE Z Amps/1y April 9, 1963 M. E. LINDSAY 3,084,678

INTERNAL COMBUSTION ENGINE WITH SHIFTING CYLINDERS Filed April 15, 1960 4 Sheets-Sheet 2 INVENTOR.

MAl/R/(g l/A os ly A GENT M. E. LINDSAY April 9, 1963 INTERNAL COMBUSTION ENGINE WITH SHIFTING CYLINDERS Filed April 15,.1960

4 Sheets-Sheet 3 INVENTOR.

(IR/CE 5 Z nvasay M. E. LINDSAY April 9, 1963 INTERNAL COMBUSTION ENGINE WITH SHIFTING CYLINDERS Filed April 15, 1960 4 Sheets-Sheet 4 M MY B scwr nite Sates This invention relates to internal combustion engines and is particularly concerned with two cycle engines of the opposed piston type wherein a pair of pistons operate oppositely in cylinders that are in communication with each other, it being a general object of this invention to provide an internal combustion engine of higher horsepower rating per pound of engine weight and particularly a two cycle engine that is capable of being supercharged.

Heretofore, engines of the two cycle type have had limited application due to the fact that substantial inefliciency is inherent therein. However, these engines can be very practical and reliable when ported properly for the speed and power required etc. One of these practical engines is the opposed piston type wherein, as above indicated, a pair of pistons operate oppositely and usually in a single common cylinder. Such an engine will ordinarily have a uniflow inlet and exhaust pattern that involves an inlet port opening at the side wall at one end of the cylinder and an exhaust port opening at the side wall at the other end of the cylinder. The said inlet and exhaust ports are simultaneously and alternately covered and uncovered by the pistons operating at the respective opposite ends of the cylinder, to the end that flow of gases occurs in one direction or axially of the cylinder. Also, in some engines inlet and/ or exhaust valves are employed and opened and closed through operation of a cam shaft and related gear, and the like.

In two cycle engines, and especially in opposed piston engines of the uniflow type, supercharging is not ordinarily possible and scavenging is commonly resorted to in order to improve operation. The fundamental reason for the state of the art is that the porting in two cycle engines involves, first the opening of the exhaust port followed by opening of the inlet port, and conversely, first the closing of the inlet followed by closing of the exhaust. As a result, on the compression stroke the exhaust port remains open a substantial time after the inlet port is closed, thus shortening the inlet period after which there is an ineffective period until the exhaust port is closed. Since the exhaust port is open at the time the inlet port is closed there is no opportunity to pressurize and supercharge the inlet gases. It is recognized that modification of two cycle engines can be employed, as for example the use of cam operated valves, but not in keeping with the simplicity and efiiciency that is actually possible with a two cycle, or two stroke, engine without valve gear.

An object of this invention is to provide a true two cycle, two stroke, internal combustion engine wherein the exhaust port not only opens before the inlet port but also wherein the exhaust port closes before the inlet port closes. With the structure that I provide there is a lengthened period for intake with the inherent possibility of pressurizing and supercharging the intake gases, when desired.

Another object of this invention is to provide a two cycle engine of the character referred to wherein the cylinder, or cylinders, can be positioned to vary the porting characteristics of the engine. As shown, the cylinder, or cylinders, is movable on its axis so as to vary the position of the port, or ports, relative to the piston, or pistons, operating therein and acting to open and close said port. or ports. In other words, the axial extent of the ports is increased and/ or decreased by suitable positioning of the cylinders.

atent It is an object of this invention to provide a two cycle engine of the character referred to wherein separate cylinders can be individually positioned to vary the port characteristics at opposite pistons, respectively. With the structure that I provide, one movable cylinder positions the exhaust port while the other movable cylinder positions the inlet port, and two said cylinders are positioned relative to the rotative position or positions of the crank or cranks that are turned by the said pistons and usual connecting rods. The two crankshafts are geared togeth- It is still another object of this invention to provide a two cycle engine of the character referred to wherein separate opposed cylinders are independently movable in synchronism with the rotative position of their respective crankshafts. As shown, the opposite crankshafts are geared together with the pair of positioned cylinders aligned and in open communication with each other. The cylinders are shifted by the rotating crankshafts, respectively, and preferably by eccentrics or cams or similar means coupled with or to said individual cylinders that are to be shifted.

The various objects and features of the present invention will be fully understood from the following detailed description of the typical preferred forms and applications thereof throughout which description references made to the accompanying drawing in which:

FIG 1 is a transverse sectional view of an internal combustion engine embodying the present invention and showing the parts and elements thereof positioned at Top Dead Center. FIG. 1a is a perspective view of a. typical cylinder that I employ in carrying out this invention. FIG. 2 is a view similar to FIG. 1 and shows the parts and elements positioned at 65 Before Bottom Dead Center. FIG. 3 is )8. view similar to FIGS. 1 and 2 and shows the parts and elements positioned at 50 Before Bottom Dead Center. FIG. 4 is a view similar to FIGS. 1 through 3 and shows the parts and elements positioned at 55 After Bottom Dead Center. FIG. 5 is a view similar to FIGS. 1 through 4 and shows the parts and elements positioned at After Bottom Dead Center. FIG. 6 is an enlarged sectional view taken as indicated by line 66 on FIG. 1. FIG. 7 is an enlarged sectional view taken as indicated by line 7-7 on FIG. 4. FIG. 8 is a detailed sectional view of a portion of the structure and shows a modified form of operating means for shifting the cylinders. FIG. 9 is a view showing the operating elements of the means shown in FIG. 8 and taken as indicated by line 9-9 on FIG. 8. FIG. 10 is a sectional view of the portion of the structure and shows a modification of the combustion chamber as it involves the cylinders, the pistons, and sealing means therefor. And, FIG. 11 is a sectional view taken as indicated by line 1111 on FIG. 10.

The two cycle, or two stroke, engine of the present invention is preferably of the opposed piston and uniflow type, it being understood that the shifting cylinder principle herein disclosed can be applied equally as well to other kinds of engines. As is clearly illustrated throughout the drawings a typical embodiment of the invention involves, generally, a frame A, oppositecylinders B and C, opposed pistons D and E operating in the cylinders, opposite crankshafts F and G operated by the pistons D and E respectively, and means H and I operated by the crankshafts F and G and positioning the cylinders B and C respectively. The cylinders B and C are shiftably carried by the frame A in accordance with the present invention, to shift axially and independently of one another, and said cylinders are ported one with an inlet port X and the other with the exhaust port Y. If so desired, and in its preferred form, the engine in- 3 cludes a prcssurizing means Z for supercharging the intake of the engine and directing gases under pressure through the inlet port X when it is opened.

The frame A can vary widely and is the main sup porting structure of the engine. That is, the frame A acts to carry the various working parts that are involved, including the parts and elements B through I, as above set forth. Generally, the frame A involves a central cylinder carrying portion 1t) and opposite crankcases 11 and 12. The portion is, in the case illustrated, jacketed as at 13 to circulate a coolant in order to dissipate heat, and there is an inlet passage 14 at one side of the portion 10 and an exhaust passage 15 at the other side thereof. As shown, the said inlet and exhaust passages 14 and 15 enter the frame A at the side thereof, preferably the top side, and through an inlet manifold 16 and an exhaust manifold 17. Thus, it will be apparent that a plurality of pairs of aligned cylinders can be employed in a single engine, said engine being characterized by one or more guideways 18, each adapted to shiftably carry a pair of opposite and independent shiftable cylinders B and C. The guideway 18 is shown as a cylindrical bore extending through the frame A from the crankcase 11 to the crankcase 12 and the passages 14 and 15 open into the guideway 18 at the side walls of the bore forming the same and each adjacent the crankcase 11 and 12, respectively. The crankcases 11 and 12 are closed by suitable covers and the engine can include any and all of the usual accessories, all carried and supported by the frame A, all as circumstances require.

The cylinders B and C are like sleeve-shaped elements independently and shiftably carried in the guideway 18 above described. The characteristic feature of the present invention is that the cylinders B and C are shiftable on their respective axes, preferably on a common axis when carried in the straight bore of the guideway 18. It is to be understood that the cylinder configuration can vary widely, as for an example partial cylinders or parts of cylinders can be employed, for instance two cylinder halves separated along a longitudinal plane can be operated independently of each other to control inlet and exhaust ports separately. As shown, the sleeve-shaped cylinder B has a turned outer wall 29 slidably engaged with the bore of the guideway 18 and it has a cylindrical inner wall 21 to slidably receive the piston D at the inlet side of the engine. The cylinder B is sealed with the frame A in any suitable manner as by rings 22 engaging the bore of the guideway 18, and the outer end portion of the cylinder B is ported at 23 to be in open communication with the inlet passage 14 that receives inlet gases from the manifold 16. In carrying out the invention the opening or passage 14 surrounds the cylinder B and is of an axial extent to remain in communication with the ports at 23 throughout the shifting of said cylinder.

The cylinder C, like the cylinder B, has a turned outer wall slidably engaged with the bore of the guideway 18 and it has a cylindrical inner wall 31 to slidably receive the piston E at the exhaust side of the engine. The cylinder C is sealed with the frame A in any suitable manner as by rings 32 engaging the bore of the guideway 18, and the outer end portion of the cylinder C is ported at 33 to be in open communication with the exhaust passage 15 that discharges exhaust gases into the manitold 17. In carrying out the invention the opening or passage 15' surrounds the cylinder C and is of an axial extent to remain in communication with the ports at 33 throughout the shifting of said cylinder. The cylinders B and C, respectively, are suitably proportioned so as not to interfere with each other during their movements as later described, and leaving a space therebetween at the center of the engine for the accommodation of fuel injecting means or ignition means, as the case may be.

In carrying out the invention, the cylinders B and C are rotatively positioned in the guideways 18 and, as shown in FIG. 1a, the cylinders are formed with elongate openings forming the ports 23 and/ or 33 and with parallel sides 71. The openings 70 enter the walls of the cylinders from the outer ends thereof and terminate at a point suitable for the action desired and the sides 71 of the openings engage with guides 72 that project radially inward from the cylindrical bores of the guideways 18. The guides 72 complete the cylindrical configuration for operating engagement of the pistons therein and establish the outermost dimension or axial extent of the ports 23 and 33. Notice, however, that the opposite dimension or axial extent of the ports 23 and 33 are varied as the cylinders B and C are shifted, all as later described.

The pistons D and E are opposed and are slidably engaged in the cylinders B and C, respectively. The piston D has a top 25 with a depending skirt 26 and there is a wrist pin 27 extending transversely thereof for pivotal connection with a connecting rod 28, and the piston E has a top 35 with a depending skirt 36 and there is a wrist pin 37 extending transversely thereof for pivotal connection with a connecting rod 38. The pistons D and E are independently moved relative to each other in opposite directions, either toward each other or apart, to either compress a gas charge or to be moved by an expanding charge.

The crankshafts F and G are alike, the shaft F being rotatably supported at or in the crankcase 11 and the shaft G being rotatably supported at or in the crankcase 12. As shown, the crankshaft F has a throw 29 for driving connection with the rod 28 and the crankshaft G has a throw 39 for driving connection with the rod 38. The two shafts F and G can have as many throws 29 and 39, respectively, as desired and commensurate with the number of cylinders in the particular engine involved, and the two crankshafts are geared together to operate in unison (the gear train not shown). Thus, the pair of pistons D and E are moved together and apart in the usual manner and so as to cover and to uncover the inlet and exhaust ports X and Y at 23 and 33, respectively.

In accordance with the present invention, I provide the means H and I that shift the cylinders B and C in a positive predetermined manner. The said means H and I are essentially alike, one of said means being associated with the crankshaft F and the other with the crankshaft G, and said means can vary widely in specific design and construction. That is, the means H and I, which are operating means for moving the cylinders, can be of the cam and follower type or as is shown in the first form of the invention can be of the eccentric motion type. In the first case illustrated the means H and I are of the latter eccentric motion type and are directly associated with the crankshafts F and G. The operating means H involves an eccentric throw 50 adjacent the throw 29 and formed on the crankshaft D to turn therewith. Further, the means H includes a drive connection between the throw 50' and the cylinder B and preferably in the form of a connecting rod 51 having driving connection with the said throw 58 and coupled to the cylinder B by a drive pin 52.

The operating means I involves an eccentric throw 60 adjacent the throw 39 and formed on the crankshaft E to turn therewith. Further, the means I includes a drive connection between the throw 60 and the cylinder C and preferably in the form of a connecting rod 61 having driving connection with said throw 60 and coupled to the cylinder C by a drive pin 62. Thus, it will be apparent that the cylinders B and C are shifted and positioned in a predetermined manner in response to the rotative position of the two cranks F and G.

In a second form of the invention, shown in FIGS. 8 and 9, the means H and I are of the cam and followertype and are also directly associated with the crankshafts F and G. In the case now under consideration the operating means H involves a dual cam 50- adjacent the throw 29 and formed on the crankshaft D to turn therewith. Further, the means H includes a drive connection between the dual cam 50 and the cylinder B and in this case is in the form of a drive frame 52 and followers or rollers 53 and 54. The dual cam 50 has two separate peripheral configurations, preferably side by side, one characterized by a high lobe portion 55 and the other characterized by a low depressed portion 56. The said portions 55 and 56 are diametrically opposite and the cam drive is of the Desmodromic type wherein the diametrically opposite peripheries of the dual cam 50 are equally spaced at all rotative positions and so that the opposite rollers 53 and 54 are engaged with their respective cam peripheries at all times. As shown, the roller 53 engages the periphery of the cam element having the lobe portion 55 while the roller 54 engages the periphery of the cam element having the low depressed portion 56. The diametrically positioned rollers 53 and 54 are rotatably carried on spaced parallel axes by the frame 52, the axis of the rotatable dual cam 50 being coincidental with a plane extending between the two roller axes and also parallel therewith.

Further, the frame 52 is guided for reciprocating rectilinear motion and so that it is connected directly with the cylinder B to move the same axially, as is required in accordance with the present lnvention and as hereinbefore disclosed. It is to be understood that the drive herein v disclosed can be used to positively operate valves such as poppet valves and the like as ordinarily arranged in single crankshaft engines.

The operating means I is the same as the means H above described and it includes dual cam adjacent the throw 39 and formed on the crankshaft E to turn therewith. Further, the means I includes a drive connection between the dual cam and the cylinder C and in the form of a drive frame and rollers or followers. With the Desmodromic drive, as herein disclosed there is positive positioning of the cylinders B and C, the same as with the eccentric drive as first disclosed, and with the advantage of accelerated or decelerate'd positioning of the said cylinders B and C relative to the rot-ative positions of their respective crankshafts D and E.

In FIGS. 10 and 11 of the drawings I have shown a modified arrangement of the present invention wherein the cylinders B and C cooperate with a head 80 for sealing engagement and wherein the pistons D and E are dome-shaped in order to gain high compression ratios. A feature of the present invention is the substantial travel of the sleeve-shaped movable cylinders and it is necessary that said cylinders be sealed with the frame A Where exposed to combustion chamber pressures. In the form of invention now under consideration a head 80' is provided intermediate the two cylinders B and C and in this case within a frame A. The head 80 is a ringshaped annular element having a center portion 81 projecting radially inward from the bore of the guideway 18, there being one or more fuel igniting and/or fuel injecting means entering into the combustion area through said portion 81. Further, the head 80 involves a pair of oppositely projecting axially disposed sleeves 82 and 83, projecting or continuing from the center portion in opposite directions, other toward the cylinder C. The sleeves 82 and 83 are spaced from the bore of the guideway '18 to slidably receive the inner end portions of the cylinders B and C, respectively, said sleeves being of axial extent so as to remain in covering engagement with the cylinders throughout movement of said cylinders.

in order to seal the combustion chamber that is established between the two pistons D and E the sleeves 82 and 83 are provided with external rings 84 and 85 that wipe the inner diameter of the cylinders B and C, respectively. Further, the cylinders B and C are provided with external rings 86 and 87 that wipe the bore of the guideway 18'. The rings 84 and 85 are at opposite ends of the head 80, while the rings 86 and 87 are at the inner ends of the cylinders B and C, all as clearly shown in the drawings. In practice, the rings one toward the cylinder B and the series of three ignition means closed at about 55 6 are split and threaded into position and suitably locked.

As shown in FIG. ll there is a plurality of ignition and/ or injecting means 90 and 91. That is, there is a series of one or both of said means. In accordance with the invention, there can be three ignition means 90, each comprising a spark plug positioned outside of the inner diameter of the head 80 and in communication with the combustion chamber through a venturi-shaped passage 96. The passage 96 is flattened in a transverse plane and is slightly constricted as shown in'FIG. 11 with sides that merge with the inner diameter of the head. The general axis of the passage is canted so that circular motion is imparted to the injection and/ or ignition. I have shown a 90, equally spaced, and with three equally spaced intermediate fuel injecting means '91 therebetween. The said means 91 can be of any suitable type.

The structural essentials of the present invention are hereinabove described and it will be apparent that said essential features can be varied and designed to meet a wide range of requirements. For example, the number and diameter and length of cylinders can be varied, the exact piston design can also be varied and the porting X and Y and use of pressurizing means Z can be applied and modified, all without deviating from the idea of means herein disclosed. In a preferred, or suggested embodiment as shown in the drawings, the engine structure can be built and can be proportioned to function as follows:

The beginning of the power stroke is shown in FIG. 1 wherein the ports at 23 and 33 are closed by the pistons D and E shown at Top Dead Center. In FIG. 2 the exhaust port at 33 begins to open at about 65 Before Bottom Dead Center at which point the exhaust gases begin to escape through the opening or passage 15. In FIG. 3 the inlet port 23 begins to open at about 50 Before Bottom Dead Center at which point the already moving exhaust gases induce the inlet of a new charge of gases. In FIG. 4- the exhaust port at 33 is finally After Bottom Dead Center at which point the inlet port at 23 remains open. In FIG. 5 the inlet port at 23 is finally closed at about 90 After Bottom Dead Center at which point the compression period begins. It is to be observed that the exhaust port is finally closed at approximately 35 in advance of the closing of the inlet port with the result that there is an interval within which to charge the cylinders with closed exhaust porting, and more important there is a substantial period within which to pressurize said intake charge as by means of the supercharging means Z.

In order to accomplish the foregoing, sequential functions, I can employ one or two moving cylinders B and/ or C. That is, it is feasible to employ a single moving cylinder either at B or C, or as is preferred both cylinders are moved in carrying out the form of invention illustrated. The eccentrics 59 or 60 are located and rotatively positioned so that the exhaust port at 33 is shifted inwardly toward the center of the engine during the beginning of the exhaust period, at which time the inlet port at 23 is shifted outwardly. Conversely, the inlet port 23 is shifted inwardly toward the center of the engine during the ending of the inlet period at which time the exhaust port at 33 is shifted outwardly and already closed. Thus, it will be apparent that the piston D and cylinder B, and the piston E and cylinder C move reversely or oppositely, at least to some extent. In practice, the eccentric throw 50 is rotatively positioned approximately 65 behind the throw 29, while the eccentric throw 663 is rotatively positioned approximately behind the throw 39, in the particular case illustrated. As a result, there is induction of inlet gases by the previously released exhaust gases and there is also a period wherein the inlet gases can be compressed by an external compressing means Z, as is clearly indicated in the drawings.

From the foregoing it will be apparent that I have pro vided an internal combustion engine having a lengthened PSI and prolonged inlet period during which the cylinders can be more adequately charged. Further, with the increased inlet period there is a predetermined period during which the exhaust port at 33 is closed and during which it is possible to pressurize the gases before closing of the said inlet port at 23. As a result, the engine is supercharged at the intake manifold 14 by the pressurizing means Z in the form of a blower or the like, as circumstances require.

Having described only the typical preferred forms and applications of my invention, I do not wish to be limited or restricted to the specific details herein set forth, but I Wish to reserve to myself any modifications or variations that may appear to those skilled in the art and fall'within the scope of the following claims.

Having described my invention, I claim:

1. In a reciprocating engine having a frame with a pair of spaced fluid passages therein and a pair of opposite crankshafts rotatably carried by the frame, a pair of independent cylinders and each shiftably supported in the frame and each With a port in communication with one of said passages in the frame, opposed pistons and one operating in each of the cylinders and each connected with a crankshaft respectively, and means operating to independently shift the cylinders in the frame during operation of the engine.

2. In a reciprocating engine having a frame with a pair of spaced fluid passages therein and a pair of opposite crankshafts rotatably carried by the frame, a pair of independent cylinders and each shiftably supported in the frame and each With a port in communication with one of said passages in the frame, opposed pistons and one operating in each of the cylinders and each connected with a crankshaft respectively, and means operating from a crankshaft to independently shift the cylinders in the frame during operation of the engine.

3. In a reciprocating engine having a frame with a pair of spaced fluid passages therein and a pair of opposite crankshafts rotatably carried by the frame, a pair of independent cylinders and each shiftably supported in the frame and each with a port in communication with one of .said passages in the frame, opposed pistons and one operating in each of the cylinders and each connected with a crankshaft respectively, and means comprising eccentrics on the opposite crankshafts and each operatively coupled to one of the shiftable cylinders to shift them independently in the frame during operation of the engine.

4. In a reciprocating engine having a frame with a pair of spaced fluid passages therein and a pair of opposite crankshafts rotatably carried by the frame, a pair of independent cylinders and each shiftably supported in the frame and each having a port therein in open communication with one of said passages in the frame, opposed pistons and one operating in each of the cylinders to cover and uncover said ports respectively and each connected with a crankshaft respectively, and means operating to independently shift the cylinders in the frame during operation of the engine.

5. In a reciprocating engine having a frame with a pair of spaced fluid passages therein and a pair of opposite crankshafts rotatably carried by the frame, a pair of independent cylinders and each shiftably supported in the frame and each having a port therein in open communication with one of said passages in the frame, opposed pistons and one operating in each of the cylinders to cover and uncover said ports respectively and each connected with a crankshaft respectively, and means operating from a crankshaft to independently shift the cylinders in'the frame during operation of the "engine.

6. In a reciprocating engine having a frame With a pair of spaced fluid passages therein and a pair of opposite crankshafts rotatably carried by the frame, a pair of independent cylinders and each shiftably supported in the frame and each having a port therein in open communication with one of said passages in the frame, opposed pistons and one operating in each of the cylinders to cover and uncover said ports respectively and each connected With a crankshaft respectively, and means comprising eccentrics on the opposite crankshafts and each operatively coupled to one of the shiftable cylinders to shift them independently in the frame during operation of theengine.

7. In a reciprocating engine having a frame with a pair of spaced fluid passages therein and a pair of opposite crankshafts rotatably carried by the frame, a pair of independent cylinders and each shiftably supported in the frame and each having a port communicating with one of said fluid passages, opposed pistons and one operating in each'of the cylinders and each connected with a crankshaft respectively, and means comprising cams on the opposite crankshafts and each operatively coupled to one of the shiftable cylinders to shift them independently in the frame during operation of the engine.

8. In a reciprocating engine having a frame with a pair of spaced fluid passages therein and a pair of opposite crankshafts rotatably carried by the frame, a pair of independent cylinders and each shiftably supported in the frame and each having a port therein in open communication with one of said fluid passages, opposed pistons and one operating in each of the cylinders to cover and uncover said ports respectively and each connected with a crankshaft respectively, and means comprising cams on the opposite crankshafts and each operatively coupled to one of the shiftable cylinders to shift them independently in the frame during operation of the engine.

References (Zited in the file of this patent UNITED STATES PATENTS 1,072,766 

1. IN A RECIPROCATING ENGINE HAVING A FRAME WITH A PAIR OF SPACED FLUID PASSAGES THEREIN AND A PAIR OF OPPOSITE CRANKSHAFTS ROTATABLY CARRIED BY THE FRAME, A PAIR OF INDEPENDENT CYLINDERS AND EACH SHIFTABLY SUPPORTED IN THE FRAME AND EACH WITH A PORT IN COMMUNICATION WITH ONE OF SAID PASSAGES IN THE FRAME, OPPOSED PISTONS AND ONE OPERATING IN EACH OF THE CYLINDERS AND EACH CONNECTED WITH A CRANKSHAFT RESPECTIVELY, AND MEANS OPERATING TO INDEPENDENTLY SHIFT THE CYLINDERS IN THE FRAME DURING OPERATION OF THE ENGINE. 